Problem: Expand.
Solution: We expand the parentheses using the distributive property : $ A(B+C+D)= A\cdot B+ A\cdot C+ A\cdot D$ We can also think about the problem using an area model: $p^2$ $-p$ $-1$ $-p^2$ Here's how the solution goes, algebraically: $\begin{aligned} &\phantom{=}{-p^2}(p^2-p-1) \\\\ &={-p^2}(p^2)+({-p^2})(-p)+({-p^2})(-1) \\\\ &=-p^4+p^3+p^2 \end{aligned}$ Here's how the solution looks in terms of the area model: $-p^4$ $p^3$ $p^2$ $p^2$ $-p$ $-1$ $-p^2$ In conclusion, $-p^2(p^2-p-1)=-p^4+p^3+p^2$